Jacobs R, Bobbert M F, van Ingen Schenau G J
Department of Functional Anatomy, Faculty of Human Movement Sciences, Vrije Universiteit, van de Boechorststraat, Amsterdam, The Netherlands.
J Biomech. 1996 Apr;29(4):513-23. doi: 10.1016/0021-9290(95)00067-4.
The main result of this study is that biarticular leg muscles contribute significantly to the work done at joints, due to transfer of power during explosive leg extensions. In particular, a net power transfer was shown from hip to knee joint during jumping and sprinting. Seven elite athletes performed explosive one legged jump and spring push offs. Kinematics, ground reaction forces and electromyography (EMG) of leg muscles were recorded. The mechanical output of six individual muscle groups was estimated by using Hill-based muscle models. The EMG and kinematics served as input to these models. For jumping as well as for sprinting, the model estimated similar results for the relative work contribution done about a joint due to transfer of power by the biarticular muscles. Rectus femoris showed a power transfer from hip to knee joint, while in contrast hamstrings showed a power transfer from knee to hip joint. Regardless of these opposite directions of power transfer, a net transfer occurred from the hip to the knee joint. The relative work contribution of hamstrings done in hip extension was 7% in jumping and 11% in sprinting. For rectus femoris, the relative work contribution done in knee extension was 21% in jumping and 31% in sprinting. Power transferring actions by gastrocnemius from knee to ankle contributed 25% in jumping and 28% in sprinting to the work done in plantar flexion. These results support the hypothesis that the action of biarticular muscles contributes to a net transfer of power from proximal to distal joints during explosive leg extensions. This action of the biarticular muscles causes an efficient conversion of body segment rotations into the desired translation of the body centre of gravity.
本研究的主要结果是，在爆发性腿部伸展过程中，由于力量的传递，双关节腿部肌肉对关节所做的功有显著贡献。特别是，在跳跃和短跑过程中，显示出从髋关节到膝关节的净功率传递。七名精英运动员进行了爆发性单腿跳跃和短跑起跑。记录了腿部肌肉的运动学、地面反作用力和肌电图（EMG）。使用基于希尔的肌肉模型估计了六个单独肌肉群的机械输出。肌电图和运动学作为这些模型的输入。对于跳跃和短跑，该模型估计了由于双关节肌肉的力量传递而在关节处完成的相对功贡献的类似结果。股直肌显示出从髋关节到膝关节的功率传递，而相比之下，腘绳肌显示出从膝关节到髋关节的功率传递。尽管功率传递方向相反，但仍发生了从髋关节到膝关节的净传递。腘绳肌在髋关节伸展中所做的相对功贡献在跳跃时为7%，在短跑时为11%。对于股直肌，在膝关节伸展中所做的相对功贡献在跳跃时为21%，在短跑时为31%。腓肠肌从膝关节到踝关节的功率传递动作在跳跃时对跖屈所做功的贡献为25%，在短跑时为28%。这些结果支持了这样的假设，即在爆发性腿部伸展过程中双关节肌肉的作用有助于从近端关节到远端关节的净功率传递。双关节肌肉的这种作用导致身体节段旋转有效地转化为身体重心的期望平移。
